Vertical type memory device

ABSTRACT

A semiconductor device, comprising: a plurality of memory cell strings; a bitline; and an interconnection coupling at least two of the memory cell strings to the bitline. Memory cell strings can be coupled to corresponding bitlines through corresponding interconnections. Alternate memory cell strings can be coupled to different bitlines through corresponding different interconnections.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35USC §119 to Korean Patent Application No. 10-2012-0110751, filed on Oct.5, 2012, the entirety of which is hereby incorporated by reference.

BACKGROUND

The present general inventive concept relates to semiconductor devicesand, more particularly, to vertical type memory devices.

In order to achieve superior performance and lower cost, there is anongoing need for increasing the density of a semiconductor device.Especially, the density of the semiconductor device is an importantdeterminant for pricing products. Since the density of a conventionaltwo-dimensional semiconductor memory device is mainly decided by an areaoccupied by a unit memory cell, the density is significantly affected bythe level of a fine patterning technology. However, ultra-high costequipment is required to achieve such fine patterns. Hence, there isstill a limitation in increasing the density of the two-dimensionalsemiconductor memory device.

SUMMARY

In one embodiment, a semiconductor device includes a plurality ofvertically stacked memory cell strings, a bitline, and aninterconnection coupling at least two of the vertically stacked memorycell strings to the bitline.

In another embodiment, a portion of the interconnection extends in afirst direction and the bit line extends in a second direction.

In some embodiments, the bit line extends substantially parallel withthe interconnection.

In one embodiment, the at least two of the memory cell strings aredisposed along the second direction and offset from the bitline in thefirst direction and the portion of the interconnection protrudes in thesecond direction.

In another embodiment, the bitline, the interconnection, and the atleast two of the memory cell strings referred to as a first bitline, afirst interconnection, and a first set of at least two of the memorycell strings, the semiconductor device further comprising: a secondbitline; and a second interconnection coupling a second set of at leasttwo of the memory cell strings to the second bitline.

In one embodiment, a portion of the first interconnection protrudes in asecond direction and the second interconnection protrudes in a directionopposite the second direction.

According to one aspect of the inventive concepts, a method includesforming a plurality of memory cell strings; coupling an interconnectionto at least two of the memory cell strings; and coupling a bitline tothe interconnection.

According to another aspect of the inventive concepts, a method offabricating a semiconductor device comprises forming a buffer dielectriclayer over a semiconductor substrate; repeatedly forming a stack of asacrificial layer and an insulating layer over the buffer dielectriclayer; forming vertical pillars extending through the stack ofsacrificial layer and the insulating layer to be connected to thesemiconductor substrate; forming separation regions by patterning thebuffer dielectric layer, the sacrificial layer, and the insulatinglayers to expose a portion of the substrate; removing the patternedsacrificial layers to form recessed regions that expose portions ofsidewalls of the vertical pillars; forming information storage elementsin the recessed regions; forming a conductive layer on the informationstorage elements in the recessed regions, thereby forming memory cellstrings including first and second string selection lines that arespaced apart from each other; forming first contacts on the verticalpillars; forming sub-interconnections on the first contacts tointerconnect the vertical pillars with the first and second stringselection lines; forming second contacts on the first and secondsub-interconnections; and forming bitlines on the second contacts, wherethe first sub-interconnections and the second sub-interconnections areconnected to other adjacent bitlines through the second contacts.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concept will become more apparent in view of the attacheddrawings and accompanying detailed description. The embodiments depictedtherein are provided by way of example, not by way of limitation,wherein like reference numerals refer to the same or similar elements.The drawings are not necessarily to scale, emphasis instead being placedupon illustrating aspects of the inventive concept.

FIG. 1 is a block diagram of a memory device according to embodiments ofthe inventive concept.

FIG. 2 is a block diagram illustrating an example of a memory cell arrayin FIG. 1.

FIG. 3 is a perspective view of a memory block of a vertical type memorydevice according to first embodiments of the inventive concept.

FIGS. 4A to 4I are enlarged views of “A” in FIG. 3.

FIGS. 5A, 5C, and 5D are top plan views of the vertical type memorydevice in FIG. 3, and FIG. 5B is a cross-sectional view taken along theline A-A′ in FIG. 5A.

FIG. 6A to FIG. 12A are top plan views corresponding to FIG. 5A, andFIGS. 6B to 12B are cross-sectional views corresponding to FIG. 5B.

FIG. 13 is a perspective view of a memory block of a vertical typememory device according to second embodiments of the inventive concept.

FIG. 14A is a top plan view of the vertical type memory device in FIG.13, and FIG. 14B is a cross-sectional view taken along the line A-A′ inFIG. 14A.

FIGS. 15A to 18A are top plan views corresponding to FIG. 14A, and FIGS.15B to 18B are cross-sectional views corresponding to FIG. 14B.

FIG. 19 is a perspective view of a memory block of a vertical typememory device according to third embodiments of the inventive concept.

FIGS. 20A and 20C are top plan views of the vertical type memory devicein FIG. 19, and FIG. 20B is a cross-sectional view taken along the lineA-A′ in FIG. 20A.

FIG. 21 is a perspective view of a memory block of a vertical typememory device according to fourth embodiments of the inventive concept.

FIG. 22A is a top plan view of the vertical type memory device in FIG.21, and FIG. 22B is a cross-sectional view taken along the line A-A′ inFIG. 22A.

FIGS. 23A to 25A are top plan views corresponding to FIG. 22A, and FIGS.23B to 25B are cross-sectional views corresponding to FIG. 22B.

FIG. 26 is a perspective view of a memory block of a vertical typememory device according to fifth embodiments of the inventive concept.

FIG. 27A is a top plan view of the vertical type memory device in FIG.26, and FIG. 27B is a cross-sectional view taken along the line A-A′ inFIG. 27A.

FIG. 28 is a schematic block diagram illustrating an example of a memorysystem including a semiconductor device fabricated according toembodiments of the inventive concept.

FIG. 29 is a schematic block diagram illustrating an example of a memorycard including a semiconductor device fabricated according toembodiments of the inventive concept.

FIG. 30 is a schematic block diagram illustrating an example of aninformation processing system on which a semiconductor device accordingto embodiments of the inventive concept is mounted.

DETAILED DESCRIPTION

The advantages and features of the inventive concept and methods ofachieving them will be apparent from the following exemplary embodimentsthat will be described in more detail with reference to the accompanyingdrawings. It should be noted, however, that the inventive concept is notlimited to the following exemplary embodiments, and may be implementedin various forms. Accordingly, the exemplary embodiments are providedonly to disclose examples of the inventive concept and to let thoseskilled in the art understand the nature of the inventive concept.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the inventive concept. The termsused in the specification are for the purpose of describing particularembodiments only and are not intended to be limiting of the invention.As used in the specification, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising”, when used in the specification, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. Throughout the specification, thesame reference numerals denote the same elements.

The inventive concept will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the inventive concept are shown.

FIG. 1 is a block diagram of a memory device according to someembodiments of the inventive concept. Referring to FIG. 1, a memorydevice 100 according to some embodiments of the inventive concept mayinclude a memory cell array 10, an address decoder 20, a read/writecircuit 30, a data input/output (I/O) circuit 40, and a control logic50.

The memory cell array 10 may be connected to an address decoder 20through a plurality of wordlines WL and connected to the read/writecircuit 30 through bitlines BL. The memory cell array 10 includes aplurality of memory cells. For example, the memory cell array 10 isconfigured to store one or more bits in a single cell.

The address decoder 20 may be configured to operate in response to thecontrol of the control logic 50. The address decoder 20 may externallyreceive an address ADDR. The address decoder 20 decodes a row addressamong the received address ADDR to select a corresponding one of thewordlines WL. In addition, the address decoder 20 may include well-knowncomponents such as, for example, a row decoder, a column decoder, anaddress buffer, or the like.

The read/write circuit 30 may be connected to the memory cell array 10through bitlines BL and connected to the data I/O circuit 40 throughdata lines D/L. The read/write circuit 30 may be configured to operatein response to the control of the control logic 50. The read/writecircuit 30 may be configured to receive a decoded column address fromthe address decoder 20. The read/write circuit 30 may be configured toselect a bitline BL using the decoded column address. For example, theread/write circuit 30 may be configured to receive data from the dataI/O circuit 40 and write the received data into the memory cell array10. The read/write circuit 30 may be configured to read data from thememory cell array 10 and transmit the read data to the data I/O circuit40. The read/write circuit 30 may be configured to read data from afirst storage area of the memory cell array 10 and write the read datainto a second storage area of the memory cell array 10. For example, theread/write circuit 30 may be configured to perform a copyback operation.

The read/write circuit 30 may include components including a page buffer(or page register), a column selector, or the like. As another example,the read/write circuit 30 may include components including a senseamplifier, a write driver, a column selector, or the like.

The data I/O circuit 40 may be connected to the read/write circuit 30through data lines DL. The data I/O circuit 40 may be configured tooperate in response to the control of the control logic 50. The data I/Ocircuit 40 is configured to exchange data DATA with an external device.The data I/O circuit 40 is configured to transmit the externallyreceived data DATA to the read/write circuit 30 through the data linesDL. The data I/O circuit 40 is configured to output the data DATAtransmitted through the data lines DL to the external device. Forexample, the data I/O circuit 40 may include components such as a databuffer, etc.

The control logic 50 may be connected to the address decoder 20, theread/write circuit 30, and the data I/O circuit 40. The control logic 50may be configured to control the operation of the memory device 100. Thecontrol logic 50 may operate in response to an externally transmittedcontrol signal CTRL.

FIG. 2 is a block diagram illustrating an example of the memory cellarray 10 in FIG. 1. Referring to FIG. 2, the memory cell array 10 mayinclude a plurality of memory blocks BLK1˜BLKh. Each of the memoryblocks BLK1˜BLKh may have a three-dimensional structure (or verticalstructure). For example, each of the memory blocks BLK1˜BLKh may includestructures extending in first, second, and third directions alongcorresponding orthogonal axes. For example, each of the memory blocksBLK1˜BLKh includes a plurality of cell strings extending in the thirddirection and the memory blocks BLK1˜BLKh extend in the seconddirection. Additional memory blocks may extend in the first direction.Thus, the memory blocks and associated structures can extend in threedirections.

FIG. 3 is a perspective view of a vertical type memory device accordingto first embodiments of the inventive concept, and FIGS. 4A to 4I areenlarged views of “A” in FIG. 3.

Referring to FIG. 3, a substrate 110 is provided. The substrate 110 mayhave a first conductivity type, e.g., P-type. Gate structures GL may beprovided on the substrate 110. A buffer dielectric layer 121 may beprovided between the substrate 110 and the gate structures GL. Thebuffer dielectric layer 121 may include silicon oxide or other suitabledielectric materials such as high-k dielectric materials.

The gate structures GL may extend in a first direction on the substrate110. Sets of the gate structures GL may face each other and may extendin a second direction on the substrate 110 where the second direction isdifferent from the first direction. For example, the second directionmay be substantially orthogonal to the first direction. The gatestructures GL may include insulating patterns 125 and gate electrodesG1˜G6 spaced apart from each other with the insulating patterns 125interposed therebetween. The gate electrodes G1˜G6 may include first tosixth gate electrodes G1˜G6 that are sequentially stacked on thesubstrate 110. The insulating patterns 125 may include silicon oxide.The buffer dielectric layer 121 may be thinner than the insulatingpatterns 125. The gate electrodes G1˜G6 may include doped silicon, ametal (e.g., tungsten), metal nitride, metal silicide, combinationsthereof, or the like. Although six gate electrodes are illustrated, anynumber of the gate electrodes that is greater than six may be present ina gate structure GL. In a particular example, the number of gateelectrodes can be selected based on a number of memory cells and controltransistors in a memory cell string.

A first separation region 131 extending in the first direction may beprovided between the gate structures GL. The first separation region 131may be filled with a first separation insulating layer (not shown, see141 in FIG. 5B). Common source lines CSL are provided in the substrate110 adjacent the first separation region 131. The common source linesCSL may be formed in the substrate 110. The common source lines CSL maybe spaced apart from each other and extend in the first direction. Thecommon source lines CSL may have a second conductivity type (e.g.,N-type) different from the first conductivity type. Unlike the figure,the common source lines CSL may have a linear conductive patternprovided between the substrate 110 and the first gate electrode G1 andextends in the first direction.

Vertical pillars PL are arranged in a matrix extending in the first andsecond directions. A plurality of vertical pillars PL may be coupledwith the gate structures GL. A plurality of vertical pillars PL areconnected to the substrate 110, and extend through the gate electrodesG1˜G6. The vertical pillars PL may have a major axis extending upwardlyfrom the substrate 110 (i.e., in the third direction). One of the endsof the vertical pillars PL may be coupled to the substrate 110, and theopposite ends may be coupled to bitlines BL1 and BL2 extending in thesecond direction.

Sub-interconnections SBL1 and SBL2 are provided between the verticalpillars PL and the bitlines BL1 and BL2. The vertical pillars PL and thesub-interconnections SBL1 and SBL2 may be optionally connected throughfirst contacts 152. The bitlines BL1 and BL2 and thesub-interconnections SBL1 and SBL2 may be optionally connected throughsecond contacts 154. The sub-interconnections SBL1 and SBL2 mayinterconnect the adjacent vertical pillars PL, which may be coupled withimmediately adjacent gate structures GL, through the first contacts 152.

A plurality of cell strings of a non-volatile memory devices such asflash memory device are provided between the bitlines BL1 and BL2 andthe common source line CSL. One single cell string may include a stringselection transistor connected to the bitlines BL1 and BL2, a groundselection transistor connected to the common source lines CSL, and aplurality of memory cells provided between the string selectiontransistor and the ground selection transistor. The selectiontransistors and the plurality of memory cells may be providedcorresponding to a single semiconductor pillar PL. A first gateelectrode G1 may be a ground selection gate line GSL of the groundselection transistor. Second to fifth gate electrodes G2˜G6 may be cellgates WL of the plurality of memory cells. A sixth gate electrode G6 maybe a string selection gate line SSL of the string selection transistor.

An information storage element 135 may be provided between the second tofifth gate electrodes G2˜G5 and the vertical pillars PL. Although it isshown in FIG. 3 that the information storage element 135 extends betweenthe gate electrodes G1˜G6 and the insulating patterns 125 and betweenthe gate electrodes G1˜G6 and the vertical pillars PL, the location andthe shape of the information storage element 135 is not limited thereto.In embodiments described later, the information storage element 135 maybe modified in various ways (see FIGS. 4A to 4I).

In one aspect, the vertical pillars PL may include a semiconductormaterial. Accordingly, the vertical pillars PL may function as channelsof transistors. The vertical pillars PL may be solid-cylindrical pillarsor hollow-cylindrical (e.g., macaroni-type) pillars. A fillinginsulating layer 127 may fill in the hollow vertical pillars. Thefilling insulating layer 127 may include silicon oxide. The fillinginsulating layer 127 may be in direct contact with the inner wall of thevertical pillars PL. The vertical pillars PL and the substrate 110 maybe a substantially continuous semiconductor structure. In this case, thevertical pillars PL may be a single-crystalline semiconductor.Therefore, the vertical pillars PL may be formed using growth techniquessuch as selective epitaxial growth (SEG). Alternatively, an interface ofthe vertical pillars PL and the substrate 110 may include a boundarysurface and/or other discontinuity. In this case, the vertical pillarsPL may be vertical pillars of polycrystalline or amorphous structureformed by, for example, chemical vapor deposition. Conductive patterns128 may be provided on one end of the vertical pillars PL. Ends of thevertical pillars PL contacting the conductive patterns 128 may form adrain region of a transistor, such as a string selection transistor.

As an example, referring to FIG. 4A, similar to FIG. 3, an informationstorage element 135 may include a blocking insulating layer 135 cadjacent to gate electrodes G1˜G6, a tunnel insulating layer 135 aadjacent to the vertical pillars PL, and a charge storage layer 135 bbetween the blocking insulating layer 135 c and the tunnel insulatinglayer 135 a. The information storage element 135 may extend between thegate electrodes G1˜G6 and both the insulating patterns 125 and verticalpillars PL. The blocking insulating layer 135 c may include a high-kdielectric (e.g., aluminum oxide or hafnium oxide). The blockinginsulating layer 135 c may be a multi-layered film comprising aplurality of thin films. For example, the blocking insulating layer 135c may include aluminum oxide and/or hafnium oxide and there may bevarious stacked orders of aluminum oxide and hafnium oxide. A chargestorage layer 135 b may be an insulating layer including a chargetrapping layer, conductive nanoparticles, or the like. The chargetrapping layer may include, for example, silicon nitride. The tunnelinsulating layer 135 a may include silicon oxide or other suitabledielectric materials.

As another example, referring to FIGS. 4B to 4D, unlike as shown in FIG.3, some portions of the information storage element 135 may not extendbetween the insulating patterns 125 and the gate electrodes G1˜G6, butsome other portions of the information storage element 135 may stillextend between the gate electrodes G1˜G6 and the vertical pillars PL.Referring to FIG. 4B, the tunnel insulating layer 135 a may extendbetween the insulating patterns 125 and the vertical pillars PL, whilethe charge storage layer 135 b and the blocking insulating layer 135 cmay extend between the insulating patterns 125 and the gate electrodesG1˜G6.

Referring to FIG. 4C, some portions of the tunnel insulating layer 135 aand the charge storage layer 135 b may extend between the insulatingpatterns 125 and the vertical pillars PL, while some portions of theblocking insulating layer 135 c may extend between the insulatingpatterns 125 and the gate electrodes G1˜G6. Referring to FIG. 4D, thetunnel insulating layer 135 a, the charge storage layer 135 b, and theblocking insulating layer 135 c may extend between the insulatingpatterns 125 and the vertical pillars PL, while the insulating patterns125 directly contact the gate electrodes G1˜G6.

Unlike the above examples, referring to FIG. 4E, the charge storagelayer 135 b may include polysilicon. In this case, the tunnel insulatinglayer 135 a, the charge storage layer 135 b, and the blocking insulatinglayer 135 c may be disposed between the gate electrodes G1˜G6, thevertical pillars PL, and the insulating patterns 125.

In another aspect, the vertical pillars PL may be conductive pillars.The vertical pillars PL may include at least one of conductivematerials, e.g., a doped semiconductor, a metal, conductive metalnitride, silicide or nanostructures (such as carbon nanotube orgraphene).

Referring to FIG. 4F, the information storage element 135 may bedisposed only between the gate electrodes G1˜G6, the vertical pillarsPL, and the insulating patterns 125.

Referring to FIGS. 4G and 4H, the information storage element 135 mayextend between the insulating patterns 125 and the vertical pillars PLor between the insulating patterns 125 and the gate electrodes G1˜G6. Inthis case, the information storage element 135 may be a variableresistance pattern. The variable resistance pattern may include at leastone of materials having variable resistance characteristics, i.e., itsresistance is variable. Hereinafter, examples of a variable resistancepattern used as the information storage element 135 will be explainedbelow.

As an example, the information storage element 135 may include amaterial whose electrical resistance may be varied depending on heatgenerated by current passing through its adjacent electrode. Thematerial may be, e.g., a phase change material. The phase changematerial may include at least one of antimony (Sb), tellurium (Te), andselenium (Se). For example, the phase change material may include achalcogenide compound in which tellurium (Te) has a concentration ofabout 20 to about 80 atomic percent, antimony (Sb) has a concentrationof about 5 to about 50 atomic percent, and the rest is germanium (Ge).In addition, the phase change material may include at least one of N, O,C, Bi, In, B, Sn, Si, Ti, Al, Ni, Fe, Dy, and La, as an impurity.Alternatively, the variable resistance pattern may be made of only oneof GeBiTe, InSb, GeSb, and GaSb.

As another example, the information storage element 135 may be formed tohave a thin film structure having an electrical resistance that may bevaried using a spin transfer procedure caused by current passing throughthe information storage element 135. The information storage element 135may have a thin film structure to exhibit magnetoresistancecharacteristics and include at least one of ferromagnetic materialsand/or at least one of antiferromagnetic materials. The informationstorage element 135 may thus include a free layer and a reference layer.

As further another example, the information storage element 135 mayinclude at least one of perovskite compounds or at least one oftransition metals. For example, the information storage element 135 mayinclude at least one of niobium oxide, titanium oxide, nickel oxide,zirconium oxide, vanadium oxide, PCMO((Pr,Ca)MnO3), strontium-titaniumoxide, barium-strontium-titanium oxide, strontium-zirconium oxide,barium-zirconium oxide, and barium-strontium-zirconium oxide.

According to some examples of the inventive concept, referring to FIG.4I, at least one of materials SW having a self-rectifying property(e.g., PN junction diode) may be provided between the informationstorage element 135 and the gate electrodes G1˜G6.

FIG. 5A is a top plan view of the vertical type memory device in FIG. 3,and FIG. 5B is a cross-sectional view taken along line A-A′ in FIG. 5A.With reference to FIGS. 5A and 5B, a vertical type memory deviceaccording to some embodiments of the inventive concept will now bedescribed in detail.

Referring to FIGS. 5A and 5B, gate structures GL may include first andsecond gate structures GL1 and GL2. A sixth gate electrode G6 of thefirst gate structure GL1 may be named as a first string selection lineSSL1, and a sixth gate electrode G6 of the second gate structure GL2 maybe named as a second string selection line SSL2. The first and secondselection lines SSL1 and SSL2 may be alternately arranged in a seconddirection.

Vertical pillars may include first and second vertical pillars PL1 andPL2 sequentially arranged in the second direction. The first and secondvertical pillars PL1 and PL2 may be arranged in a matrix of first andsecond directions. The first vertical pillars PL1 are coupled at oneside of string selection lines SSL1 or SSL2, and the second verticalpillars PL2 may be coupled at the other side thereof. Vertical pillarsimmediately adjacent in the first direction may be spaced apart fromeach other by, for example, two pitches of bitlines BL1 and BL2.

Sub-interconnections may interconnect vertical pillars PL1 and PL2 thatare coupled to different string selection lines SSL. Thesub-interconnections may include a first sub-interconnection SBL1 and asecond sub-interconnection SBL2. For example, the firstsub-interconnections SBL1 may connect second vertical pillars PL2 of onefirst string selection line SSL1 to first vertical pillars PL1 of thesecond string selection line SSL2, and the second sub-interconnectionsSBL2 may connect second vertical pillars PL2 of the second stringselection line SSL2 to first vertical pillars PL1 of another firststring selection line SSL1.

Each of the first sub-interconnections SBL1 and each of the secondsub-interconnections SBL2 may be arranged in a first direction. Thefirst and second sub-interconnections SBL1 and SBL2 may be alternatelyarranged in a second direction. The first sub-interconnections SBL1 andthe second sub-interconnections SBL2 may be connected to other bitlinesadjacent to each other. For example, the first sub-interconnections SBL1may be connected to a first bitline BL1, and the secondsub-interconnections SBL2 may be connected to a second bitline BL2.

The first sub-interconnections SBL1 may include first protrusions P1protruding in the first direction, and the second sub-interconnectionsSBL2 may include second protrusions P2 protruding in a directionopposite to the first direction.

In some embodiments, the first protrusion P1 and the second protrusionsP2 may be arranged to extend in the same direction depending on theapplication.

The protrusions P1 and P2 may extend over first separation insulatinglayers 141 between gate structures GL1 and GL2.

First contacts 152 may connect the vertical pillars PL1 and PL2 to thesub-interconnections SBL1 and SBL2. Second contacts 154 may connect thesub-interconnections SBL1 and SBL2 to the bitlines BL1 and BL2. Thefirst contacts 152 may be disposed on the vertical pillars PL1 and PL2.The second contacts 154 may be disposed on the sub-interconnections SBL1and SBL2 over the first separation insulating layers 141 between thegate structures GL1 and GL2. For example, the second contacts 154 maydirectly overlie the first separation insulating layers 141.

As illustrated in FIG. 5A, the second contacts 154 on the firstsub-interconnections SBL1 are shifted from the first contacts 152 in thefirst direction, e.g., shifted by half the pitch of the bitlines BL1 andBL2, and the second contacts 154 on the second sub-interconnections SBL2are shifted from the first contacts 152 in a direction opposite to thefirst direction, e.g., shifted by half the pitch of the bitlines BL1 andBL2. The second contacts 154 may be disposed on the protrusions P1 andP2.

FIGS. 5C and 5D illustrate modified examples of FIG. 5A. With referenceto FIGS. 5C and 5D, modified examples of a vertical type memory deviceaccording to some embodiments of the inventive concept will be explainedbelow in detail. Technical features similar to those explained in FIGS.5A and 5B will not be explained, but differences therebetween will beexplained in detail.

Referring to FIG. 5C, first sub-interconnections SBL1 may extend in asecond direction and include protrusions P1 protruding in a firstdirection. Second sub-interconnections SBL2 may have a oblong orsubstantially rectangular shape extending in the second directionwithout protrusions P1 or P2. The second contacts 154 on the firstsub-interconnections SBL1 may be shifted from the first contacts 152,and the second contacts 154 on the second sub-interconnections SBL2 maybe in line with the first contacts 152. The second contacts 154 on thefirst sub-interconnections SBL1 may be shifted from the first contacts152 in the first direction by one pitch of the bitlines BL1 and BL2.

Referring to FIG. 5D, the first and second sub-interconnections SBL1 andSBL2 may have an oblong or rectangle shape extending in the seconddirection. For example, the sub-interconnections SBL and SBL2 may havegreater width than the bitlines BL1 and BL2 and have smaller width thanthe diameter of the vertical pillars. The second contacts 154 on thefirst sub-interconnections may be shifted from the first contacts 152 inthe first direction by, for example, half the pitch of the bitlines BL1and BL2, and the second contacts 154 on the second sub-interconnectionsSBL2 may be shifted from the first contacts 152 in a direction oppositeto the first direction by, for example, half the pitch of the bitlinesBL1 and BL2. The sub-interconnections SBL1 and SBL2 have a width thatextends from the first contacts 152 to the second contacts 154.

As shown in FIGS. 5C and 5D, the sub-interconnections SBL1 and SBL2 maybe modified into various shapes. Although particular shapes and sizeshave been used as examples, in other embodiments, thesub-interconnections SBL may take other shapes, sizes, or the like.

In the above described embodiments of the inventive concept, connectingvertical pillars to bitlines through sub-interconnections according tothe technical configuration described herein allows adjacent bitlines,e.g., immediately adjacent bitlines, be disposed more closely, thusincreasing the integration density. For example, if a diameter ofvertical pillars is referred to as F when viewed from the top, aneffective area may be defined as an average area occupied by a singlechannel on a top surface. An effective area to a single channel is 6F²(2F×3F/1 channel) in the layout of a conventional VNAND arrangement,while an effective area to a single channel in first embodiment of theinventive concept is reduced to 5F² (2F×5F/2 channel). Accordingly, aunit cell area can be reduced to increase integration density.Furthermore, the number of bitlines selected by one string selectiongate, i.e., a page size may be doubled, as compared to the conventionalVNAND. Thus, program and read speeds can be improved.

A method of forming the vertical type memory device in FIG. 3 will nowbe described. FIG. 6A to FIG. 12A are top plan views corresponding toFIG. 5A, and FIGS. 6B to 12B are cross-sectional views corresponding toFIG. 5B.

Referring to FIGS. 6A and 6B, a substrate 110 is provided. The substrate110 may have a first conductivity type, e.g., P-type. A bufferdielectric layer 121 may be formed on the substrate 110. The bufferdielectric layer 121 may include, for example, silicon oxide. The bufferdielectric layer 121 may be formed by, for example, a thermal oxidationprocess. Sacrificial layers 123 and insulating layers 124 arealternately stacked on the buffer dielectric layer 121. The thickness ofan uppermost insulating layer 124U may be greater than those of theother insulating layers 124. The insulating layers 124, 124U mayinclude, for example, silicon oxide. The sacrificial layer 123 mayinclude materials having different wet etch properties (etchselectivity) with respect to the buffer dielectric layer 121 and theinsulating layers 124, 124U. The sacrificial layers 123 may include, forexample, silicon nitride, silicon oxynitride, polysilicon or polysilicongermanium. The sacrificial layers 123 and the insulating layers 124 maybe formed by, for example, chemical vapor deposition (CVD).

Referring to FIGS. 7A and 7B, vertical holes 126 are formed to exposethe substrate 110, passing through the buffer dielectric layer 121, thesacrificial layers 123, and the insulating layers 124, 124U. Thevertical holes 126 may be disposed in the same manner as the verticalpillars PL1 and PL2 explained with reference to FIG. 5A.

Referring to FIGS. 8A and 8B, vertical pillars PL1 and PL2 are formed inthe vertical holes 126. In one aspect, the vertical pillars PL1 and PL2may be semiconductor layers of a first conductivity type. Thesemiconductor layer may be formed not to fill up (i.e., partially fill)the vertical holes 126, and an insulating material may be formed on thesemiconductor layer to fill up the vertical holes 126. The semiconductorlayer and the insulating material may be planarized to expose theuppermost insulating layer 124U. Thus, cylindrical vertical pillars PL1and PL2 may be formed having the inside filled with a filling insulatinglayer 127.

Alternatively, the semiconductor layer may be formed to fill thevertical holes 126. In this case, the filling insulating layer may notbe required. Upper portions of the vertical pillars PL1 and PL2 may berecessed to be lower than the uppermost insulating layer. Conductivepatterns 128 may be formed in the vertical holes 126 in which thevertical pillars PL1 and PL2 are recessed. The conductive patterns 128may be formed of a conductive material such as doped polysilicon or ametal. Drain regions may be formed by introducing impurities of secondconductivity type into the conductive patterns 128 and upper portions ofthe vertical pillars PL1 and PL2. The second conductivity type may beN-type.

In another aspect, the vertical pillars PL1 and PL2 may include at leastone of conductive materials, e.g., a doped semiconductor, a metal,conductive metal nitride, silicide or nanostructures (such as carbonnanotube or graphene).

Referring to FIGS. 9A and 9B, the buffer dielectric layer 121, thesacrificial layers 123, and the insulating layers 124 are successivelypatented to form separation regions 131 that are spaced apart from eachother, extend in a first direction, and expose a portion of thesubstrate 110. The patterned insulating layers 124, 124U may becomeinsulating patterns 125.

Referring to FIGS. 10A and 10B, the patterned sacrificial layers 123exposed to the separation regions 131 are selectively removed to formrecessed regions 133. The recessed regions 133 correspond to regions inwhich the sacrificial layers 123 are removed and are defined by thevertical pillars PL1 and PL2 and the insulating patterns 125. If thesacrificial layers 123 include silicon nitride or silicon oxynitride, aprocess of removing the sacrificial layers 123 may be performed using anetchant containing phosphoric acid. Portions of sidewalls of thevertical pillars PL1 and PL2 are exposed to the recessed region 133.

Referring to FIGS. 11A and 11B, an information storage element 135 isformed in the recessed region 133. In one embodiment, the informationstorage element 135 may include a tunnel insulating layer contacting thevertical pillars PL1 and PL2, a charge storage layer on the tunnelinsulating layer, and a blocking insulating layer on the charge storagelayer (see, for example, FIG. 4A). In this case, the vertical pillarsPL1 and PL2 may be semiconductor pillars. The tunnel insulating layermay include silicon oxide. The tunnel insulating layer may formed bythermally oxidizing the vertical pillars PL1 and PL2 exposed to therecessed region 133. Alternatively, the tunnel insulating layer may beformed by an atomic layer deposition (ALD) process. The charge storagelayer may be a charge trapping layer or an insulating layer includingconductive nanoparticles. The charge trapping layer may include, forexample, silicon nitride. The blocking insulating layer may includehigh-k dielectric (e.g., aluminum oxide or hafnium oxide). The blockinginsulating layer may be a multi-layered film comprising a plurality ofthin films. For example, the blocking insulating layer may includealuminum oxide and silicon oxide, and there may be various stackedorders of aluminum oxide and silicon oxide. The charge storage layer andthe blocking insulating layer may be formed by the ALD process withsuperior step coverage and/or a chemical vapor deposition (CVD) process.Alternatively, when the information storage element 135 has a structureshown in FIGS. 4B to 4E, at least one of the tunnel insulating layer,the charge storage layer and/or the blocking insulating layerconstituting the information storage element 135 may be formed in thevertical holes 126 before formation of the vertical pillars PL1 and PL2.

In some other embodiments, the information storage element 135 may be avariable resistance pattern (see FIGS. 4F to 4H). The variableresistance pattern may include at least one of materials having variableresistance characteristics, i.e., its resistance being variabledepending on current passing therethrough. In this case, the verticalpillars PL1 and PL2 may be conductive pillars including conductivematerials (e.g., a doped semiconductor, a metal, conductive metalnitride, silicide or nanostructures (such as carbon nanotube orgrapheme)). When the information storage element 135 has the structureshown in FIG. 4G, the information storage element 135 may be formed inthe vertical holes 126 before formation of the vertical pillars PL1 andPL2.

A conductive layer is formed on the information storage element 135 inthe recessed region 133. The conductive layer may be formed of at leastone of doped silicon, a metal (e.g., tungsten), metal nitride, and metalsilicide. The metal conductive layer may be formed by the ALD process.When the conductive layer is a metal silicide layer, the conductivelayer may be formed by forming a polysilicon layer, removing a portionof the polysilicon layer adjacent to a first separation region 131 torecess the polysilicon layer, forming a metal layer on the recessedpolysilicon layer, thermally treating the metal layer, and removing anon-reacting metal layer. The metal layer for the metal silicide layermay include tungsten, titanium, cobalt or nickel.

The conductive layer formed outside of the recessed region 133 (i.e., inthe first separation region 131) is removed. Thus, gate electrode G1˜G6are formed in the recessed region 133. The gate electrodes G1˜G6 extendin a first direction. Gate structures GL may include the gate electrodesG1˜G6. The gate structures GL may include first and second gatestructures GL1 and GL2 that are alternately arranged in a seconddirection. The first and second vertical pillars PL1 and PL2 arranged ina matrix of the first and second directions may be coupled with one gatestructure.

The conductive layer formed in the separation regions 131 may be removedto expose the substrate 110. Impurities of second conductivity type maybe heavily introduced into the exposed substrate 110 to form commonsource lines CSL.

Referring to FIGS. 12A and 12B, a first separation insulating layer 141is formed to fill the separation regions 131. First contacts 152 may beformed on the vertical pillars PL1 and PL2. Sub-interconnections SBL1and SBL2 may be formed on the first contacts 152. Thesub-interconnections SBL1 and SBL2 may connect the vertical pillars PL1and PL2 coupled to adjacent string selection lines SSL1 and SSL2,respectively, through the first contacts 152. That is, thesub-interconnections SBL1 and SBL2 may span the first separationinsulating layers 141.

The first sub-interconnections SBL1 and the second sub-interconnectionsSBL2 may extend in the second direction. The first sub-interconnectionSBL1 may include first protrusions P1 protruding in the first direction,and the second sub-interconnections may include second protrusions P2protruding in a direction opposite to the first direction. Theprotrusions P1 and P2 may extend over the first separation insulatinglayers 143 between the gate structures GL1 and GL2.

Returning to FIGS. 5A and 5B, the first sub-interconnections SBL1 andthe second sub-interconnections SBL2 are connected to other adjacentbitlines through the second contacts 154. The first sub-interconnectionsSBL1 may be connected to the first bitline BL1, and the secondsub-interconnections SBL2 may be connected to the second bitline BL2.

FIG. 13 is a perspective view of a memory block of a vertical typememory device according to some embodiments of the inventive concept.FIG. 14A is a top plan view of the vertical type memory device in FIG.13, and FIG. 14B is a cross-sectional view taken along line A-A′ in FIG.14A. Technical features similar to those of the embodiment describedwith reference to FIG. 3 will not be explained, but differencestherebetween will be explained in detail.

Referring to FIGS. 13, 14A, and 14B, four vertical pillars PL1, PL2,PL1, and PL2 are sequentially arranged in a single gate structure GL ina second direction. The four vertical pillars PL1, PL2, PL1, and PL2 arearranged in a matrix and also extend in the first direction in the gatestructure GL.

A sixth gate electrode G6 of one gate structure GL may include first andsecond string selection lines SSL1 and SSL2. The first string selectionline SSL1 and the second string selection line SSL2 may be adjacent toeach other and alternately arranged in the second direction. A secondseparation insulating layer 142 is formed between the first stringselection line SSL1 and the second string selection line SSL2. Thesecond separation insulating layer 142 may have smaller width than thefirst separation insulating layer 141.

The first protrusions P1 may extend over the first separation insulatinglayer 141, and the second protrusions P2 may extend over the secondseparation insulating layer 142. The second contact 154 on the firstsub-interconnection 141 SBL1 may be disposed on the first separationinsulating layer 141, and the second contact 154 on the secondsub-interconnection SBL2 may be disposed on the second separationinsulating layer 142.

As shown in FIGS. 5C and 5D, the sub-interconnections SBL1 and SBL2 maybe modified into various shapes.

Referring to FIG. 14A, an effective area with respect to a singlechannel is reduced to 4F² (2F×4F/2 channel) in this embodiment of theinventive concept. Likewise, a unit cell area can be reduced to increaseintegration density. Furthermore, the number of bitlines selected by onestring selection gate, i.e., a page size may be doubled, as compared tothe conventional VNAND. Thus, program and read speeds can be improved.

A method of fabricating the vertical type memory device in FIG. 13 willnow be described. FIGS. 15A to 17A are top plan views corresponding toFIG. 14A, and FIGS. 15B to 17B are cross-sectional views correspondingto FIG. 14B. Technical features similar to the embodiment described withreference to FIGS. 6A to 12B will not be explained, but differencestherebetween will be explained in detail.

Referring to FIGS. 15A and 15B, similar to the embodiments explainedwith reference to FIGS. 6A to 8B, vertical pillars PL1 and PL2 areformed in vertical holes penetrating through a buffer dielectric layer121, sacrificial layers 123, and insulating layers 124 to expose asubstrate 110. The vertical pillars PL1 and PL2 may be recessed, andconductive patterns 128 may be formed in recessed vertical holes.

Referring to FIGS. 16A and 16B, the buffer dielectric layer 121, thesacrificial layers 123, and the insulating layers 124 may be patternedto form separation regions 131 that are spaced apart from each other.The separation regions 131 extend in the first direction, and expose aportion of the substrate 110. The patterned insulating layers 124 becomeinsulating patterns 125. The sacrificial layers 123 exposed to theseparation regions 131 are selectively removed to form a recessed region133.

Referring to FIGS. 17A and 17B, an information storage element 135 and aconductive layer are formed in the recessed region 133. The conductivelayer formed outside of the recessed region 133 (i.e., in the separationregion 131) is removed. Thus, gate electrodes G1˜G6 are formed in therecessed regions 133 described above. The gate electrodes G1˜G6 extendin the first direction.

The conductive layer formed in the separation regions 131 may be removedto expose a portion of the substrate 110. Impurities of secondconductivity type may be heavily introduced into the exposed substrate110 to form common source lines CSL.

A first separation insulating layer 141 is formed to fill the separationregions 131. A sixth gate electrode G6 is patterned to form first andsecond string selection lines SSL1 and SSL2 in the single gate structureGL. A second separation region 132 is formed between the first andsecond string selection lines SSL1 and SSL2. The first and second stringselection lines SSL1 and SSL2 are adjacent to each other and alternatelyarranged in the second direction. The first and second vertical pillarsPL1 and PL2 arranged in a matrix may be coupled with one stringselection line. For example, in this embodiment, within the single gatestructure GL, first and second vertical pillars PL1 and PL2 can becoupled to either the first and second string selection lines SSL1 andSSL2.

Referring to FIGS. 18A and 18B, a second separation insulating layer 142is formed to fill the second separation region 132. First contacts 152may be formed on the vertical pillars PL1 and PL2. Sub-interconnectionsSBL1 and SBL2 may be formed on the first contacts 152. The firstsub-interconnections SBL1 and the second sub-interconnections SBL2 mayextend in the second direction. The sub-interconnections SBL1 and SBL2may connect the vertical pillars PL1 and PL2 respectively coupled withimmediately adjacent string selection lines SSL1 and SSL2 through thefirst contacts 152, in a one-to-one correspondence.

Returning to FIGS. 14A and 14B, the first sub-interconnections SBL1 andthe second sub-interconnections SBL2 are connected to adjacent otherbitlines through the second contacts 154. The first sub-interconnectionsSBL1 may be connected to the first bitline BL1, and the secondsub-interconnections SBL2 may be connected to the second bitline BL2.

FIG. 19 is a perspective view of a memory block of a vertical typememory device according to some embodiments of the inventive concept.FIG. 20A is a top plan view of the vertical type memory device in FIG.19, and FIG. 20B is a cross-sectional view taken along the line A-A′ inFIG. 20A. Technical features similar to the embodiment described withreference to FIG. 3 will not be explained, but differences therebetweenwill be explained in detail.

Referring to FIGS. 19, 20A, and 20B, gate structures GL may includeadjacent first to third gate structures. A sixth gate electrode G6 ofthe first gate structure may be named a first string selection lineSSL1, a sixth gate electrode G6 of the second gate structure may benamed a second string selection line SSL2, and a sixth gate electrode G6of the third gate structure may be named a third string selection lineSSL3. The first to third string selection lines SSL1˜SSL3 may bealternately arranged in a second direction.

Vertical pillars PL may include vertical pillars PL1˜PL4 arranged in azigzag manner. That is, the vertical pillars PL1˜PL4 may be arrangedoffset from each other in both the first direction and the seconddirection The first and fourth vertical pillars PL1 and PL4 may bedisposed at either side of the string selection lines SSL1˜SSL3, and thesecond and third vertical pillars PL2 and PL3 may be disposed betweenthe first vertical pillars PL1 and the fourth vertical pillars PL4. Thesecond vertical pillars PL2 may be shifted from the first verticalpillars PL1 in the first direction. The fourth vertical pillars PL4 maybe shifted from the third vertical pillars PL3 in the first directionImmediately adjacent vertical pillars may be spaced apart from eachother in the first direction by two pitches of bitlines BL1˜BL4.

Sub-interconnections may include first to fourth sub-interconnectionsSBL1˜SBL4. The first sub-interconnections SBL1 may connect the thirdvertical pillars PL3 coupled to the first string selection line SSL1 tothe second vertical pillars PL2 coupled to the second string selectionline SSL2. The second sub-interconnections SBL2 may connect the thirdvertical pillars PL3 coupled to the second string selection line SSL2 tothe second vertical pillars PL2 coupled to the third string selectionline SSL3. The third sub-interconnections SBL3 may connect the fourthvertical pillars PL4 coupled to the first string selection line SSL1 tothe first vertical pillars PL1 coupled to the second string selectionline SSL2. The fourth sub-interconnections SBL4 may connect the fourthvertical pillars PL4 coupled to the second string selection line SSL2 tothe first vertical pillars PL1 coupled to the third string selectionline SSL3.

The first sub-interconnections SBL1 and the third sub-interconnectionsSBL3 may be alternately arranged in the first direction, and the secondsub-interconnections SBL2 and the fourth sub-interconnections SBL4 maybe alternately arranged in the first direction. The firstsub-interconnections SBL1 and the fourth sub-interconnections SBL4 maybe alternately arranged in the second direction, and the secondsub-interconnections SBL2 and the third sub-interconnections SBL3 may bealternately arranged in the second direction.

The first to fourth sub-interconnections SBL1˜SBL4 may be connected tocorresponding bitlines. For example, the first sub-interconnections SBL1may be connected to the first bitline BL1, the secondsub-interconnections SBL2 may be connected to the second bitline BL2,the third sub-interconnections SBL3 may be connected to the thirdbitline BL3, and the fourth sub-interconnections SBL4 may be connectedto the fourth bitline BL4.

First contacts 152 may be provided for connecting the vertical pillarsPL1˜PL4 to the sub-interconnections SBL1˜SBL4. Second contacts 154 maybe provided for connecting the sub-interconnections SBL1˜SBL4 to thebitlines BL1˜BL4. The first contacts 152 may be disposed on the verticalpillars PL1˜PL4, and the second contacts 154 may be disposed on thefirst separation insulating layers 141. For example, the second contacts154 on the first and third sub-interconnections SBL1 and SBL3 may beshifted from the first contacts 152 in the first direction by half thepitch of bitlines, and the second contacts 154 on the second and fourthsub-interconnections SBL2 and SBL4 may be shifted from the firstcontacts in a direction opposite to the first direction by a quarterpitch of bitlines. The first to fourth sub-interconnections SBL1˜SBL4may extend in the second direction. The first and thirdsub-interconnections SBL1 and SBL3 may include first to thirdprotrusions P1 and P3 protruding in the first direction, respectively.The second and fourth sub-interconnections SBL2 and SBL4 may includesecond and fourth protrusions P2 and P4 protruding in a directionopposite to the first direction, respectively. A protrusion distancebetween the first and third protrusions P1 and P3 may be two timeslonger than that between the second and fourth protrusions P2 and P4.The second contacts 154 may be disposed on the protrusions P1˜P4. Theprotrusions P1˜P4 may extend onto first separation insulating layers 141between gate structures.

FIG. 20C illustrates a modified example of FIG. 20A. With reference toFIG. 20C, a modified example of a vertical type memory device accordingto some other embodiments of the inventive concept will now be describedmore fully. Technical features similar to those explained in FIGS. 20Aand 20B will not be explained, but differences therebetween will beexplained in detail.

First and third sub-interconnections SBL1 and SBL3 may extend in asecond direction and may include protrusions P1 and P3 protruding in afirst direction. Second and fourth sub-interconnections SBL2 and SBL4may have substantially rectangular shapes that extend in the seconddirection. Second contacts 154 on the first and thirdsub-interconnections SBL1 and SBL3 may be shifted from first contacts152 in the first direction, and second contacts 154 on the second andfourth sub-interconnections SBL2 and SBL4 may not be shifted from thefirst contacts 152. For example, the second contacts on the first andthird sub-interconnections SBL1 and SBL3 may be shifted from the firstcontacts 152 in the first direction by one pitch of the bitlinesBL1˜BL4. As shown in FIG. 20C, the sub-interconnections SBL1˜SBL4 may betransformed into various shapes.

Referring back to FIG. 20A, an effective area with respect to a singlechannel is reduced to 3.3F² (2F×5F/3 channel) according to someembodiments of the inventive concept. Likewise, a unit cell area can bereduced to increase integration density. Furthermore, the number ofbitlines selected by one string selection gate, i.e., a page size mayincrease four times, as compared to the conventional VNAND. Thus,program and read speeds can be improved.

The vertical type memory device according to some embodiments of theinventive concept shown in FIG. 19 may be formed by the method describedwith reference to FIGS. 16A to 12B. Moreover, the vertical type memorydevice according to some embodiments of the inventive concept shown inFIG. 19 may be modified using the inventive concepts described withreference to FIGS. 13, 14A, and 14B, such that a sixth gate electrode G6of one gate structure GL includes first and second string channel linesSSL1 and SSL2. An effective area with respect to a single channel may bereduced less than 3.3F² (2F×5F/3 channel).

FIG. 21 is a perspective view of a memory block of a vertical typememory device according to some embodiments of the inventive concept.FIG. 22A is a top plan view of a portion of the vertical type memorydevice in FIG. 19, and FIG. 20B is a cross-sectional view taken alongline A-A′ in FIG. 20A. Technical features similar to the embodimentdescribed with reference to FIG. 3 will not be explained, butdifferences therebetween will be explained in detail.

Referring to FIGS. 21, 22A, and 22B, a substrate 110 is provided. Thesubstrate 110 may have a first conductivity type, e.g., P-type. A gatestructure GL is provided on the substrate 110. The gate structure GL mayinclude insulating patterns 125 and gate electrodes spaced apart fromeach other with the insulating patterns 125 interposed therebetween.Gate electrodes may include first to sixth gate electrodes G1˜G6 thatare sequentially stacked on the substrate 110. The insulating patterns125 may include silicon oxide. The gate electrodes G1˜G6 may includedoped silicon, a metal (e.g., tungsten), metal nitride, metal silicideor combinations thereof. Although sixth gate electrodes shown in thefigures, the number of the gate electrodes is not limited to six and maybe greater or fewer than six.

Vertical pillars PL are arranged in first and second directions, forminga matrix of vertical pillars PL. The vertical pillars PL are connectedto the substrate 110, passing through the gate electrodes G1˜G6. Thevertical pillars PL may have major axes extending upwardly (i.e., athird direction) from the substrate 110. Some ends of the verticalpillars PL may be connected to the substrate 110, and the other endsthereof may be connected to bitlines BL1 and BL2, which extend in thesecond direction.

Sub-interconnections SBL1 and SBL2 are located between the verticalpillars PL and the bitlines BL1 and BL2. The vertical pillars PL and thesub-interconnections SBL1 and SBL2 may be connected through firstcontacts 152. The bitlines BL1 and BL2 and the sub-interconnections SBL1and SBL2 may be connected through second contacts 154. Thesub-interconnections SBL1 and SBL2 may connect the vertical pillars PLcoupled with immediately adjacent gate structures GL, through the firstcontacts 152.

A plurality of cell strings of a flash memory device are providedbetween the bitlines BL1 and BL2 and the substrate 110. A single cellstring may include a string selection transistor connected to thebitlines BL1 and BL2, a ground selection transistor connected to thesubstrate 110, and a plurality of memory cells provided between thestring selection transistor and the ground selection transistor. Theselection transistors and the plurality of memory cells may be providedat a single semiconductor pillar PL. A first gate electrode G1 may be aground selection gate line GSL of the ground selection transistor.Second to fifth gate electrodes G2˜G5 may be cell gates WL of theplurality of memory cells. A sixth gate electrode G6 may be separatedinto plurality by a third separation region 133 (FIG. 21) to function assting selection lines of the string selection transistor. The stringselection lines may include first and second string selection lines SSL1and SSL2. The first and second string selection lines SSL1 and SSL2 mayextend in the first direction and may be alternately arranged in thesecond direction. Third separation insulating layers 143 are provided inthe third separation region 133 between the first and second stringselection lines SSL1 and SSL2 as shown in FIG. 22B, for example.

An information storage element 135 may be provided between the first tosixth gate electrodes G1˜G6 and the vertical pillars PL. The informationstorage element 135 may extend between the gate electrodes G1˜G6 and theinsulating patterns 125. The information storage element 135 may includea blocking insulating layer, a charge storage layer, and a tunnelinsulating layer.

The substrate 110 may be provided with a source region (not shown)forming a path of current flowing from the bitlines BL1 and BL2 or apath of current flowing to the bitlines BL1 and BL2.

Since the vertical pillars PL1 and PL2 and the sub-interconnections SBL1and SBL2 are similar to those explained with reference to FIG. 3,similar technical features will not be explained in further detail.Protrusions P1 and P2 of the sub-interconnections SBL1 and SBL2 mayextend over the third separation insulating layer 143. The secondcontacts 154 may be disposed on the sub-interconnections SBL1 and SBL2over the third separation insulating layer 143.

As shown in FIGS. 5C and 5D, the sub-interconnections SBL1 and SBL2 mayhave various shapes.

Referring to FIG. 22A, an effective area of a single channel is reducedto 4F² (2F×4F/2 channel) according to some embodiments of the inventiveconcept. Likewise, a unit cell area can be reduced to increaseintegration density. Furthermore, the number of bitlines selected by onestring selection gate, i.e., a page size may be doubled, as compared tothe conventional VNAND. Thus, program and read speeds can be improved.

A method of fabricating the vertical type memory device in FIG. 21 willnow be described in detail. FIGS. 23A to 25A are top plan viewscorresponding to FIG. 22A, and FIGS. 23B to 25B are cross-sectionalviews corresponding to FIG. 22B.

Referring to FIGS. 23A and 23B, a substrate 110 is provided. Thesubstrate 110 may have a first conductivity type, e.g., P-type.Insulating layers 124 and conductive layers 122 are alternately formedon the substrate 110. The insulating layers 124 may include, forexample, silicon oxide. The conductive layers 122 may include, forexample, doped silicon, a metal (e.g., tungsten), metal nitride, metalsilicide or combinations thereof.

Vertical holes 126 are formed to penetrate the conductive layers 122 andthe insulating layers 124 to expose the substrate 110. The verticalholes 126 may be disposed in the same manner as the vertical pillars PL1and PL2 explained with reference to FIG. 22A.

Referring to FIGS. 24A and 24B, an information storage element 135 isformed on sidewalls of the vertical holes 126. The information storageelement 135 may include a blocking insulating layer, a charge storagelayer, and a tunnel insulating layer. The information storage element135 is anisotropically etched to expose the substrate 110.

Vertical pillars PL1 and PL2 are formed adjacent to the informationstorage element 135 in the vertical holes 126. The vertical pillars PL1and PL2 are connected to the substrate 110.

In one aspect, the vertical pillars PL1 and PL2 may be semiconductorlayers of a first conductivity type. The semiconductor layer may beformed not to fill up the vertical holes 126, and an insulating materialmay be formed on the semiconductor layer to fill up the vertical holes126. The semiconductor layer and the insulating material may beplanarized to expose an uppermost insulating layer 124′. Thus,cylindrical vertical pillars PL1 and PL2 filled with afilling-insulating layer 127 may be formed. The semiconductor layer maybe formed to fill the vertical holes 126. In this case, the fillinginsulating layer may not be required. Upper portions of the verticalpillars PL1 and PL2 may be recessed to be lower than a top surface ofthe uppermost insulating layer 124′. Conductive patterns 128 may beformed in portions of the vertical holes 126 where the vertical pillarsPL1 and PL2 are recessed. The conductive patterns 128 may be dopedpolysilicon or a metal. Drain regions may be formed by introducingimpurities of second conductivity type into the conductive patterns 128and upper portions of the vertical pillars PL1 and PL2. The secondconductivity type may be N-type.

In another aspect, the vertical pillars PL1 and PL2 may include at leastone of conductive materials, e.g., a doped semiconductor, a metal,conductive metal nitride, silicide or nanostructures (such as carbonnanotube or grapheme). In this case, the information storage element maybe a variable resistance pattern.

The insulating layers 124 and the conductive layers 122 may be patternedto form insulating patterns 125 and gate electrodes G1˜G6. A sixth gateelectrode G6 may be additionally patterned to be separated into multiplegate electrodes. Thus, the sixth gate G6 may include first and secondstring selection lines SSL1 and SSL2.

Referring to FIGS. 25A and 25B, third separation insulating layers 143are provided in the third separation region 133 between the first andsecond string selection lines SSL1 and SSL2. The first contacts 152 maybe formed on the vertical pillars PL1 and PL2. Sub-interconnections SBL1and SBL2 may be formed on the first contacts 152. Thesub-interconnections SBL1 and SBL2 may interconnect the vertical pillarsPL1 with immediately adjacent vertical pillars PL2 associated withdifferent string selection lines SSL1 and SSL2 through the firstcontacts 152.

First sub-interconnections SBL1 and second sub-interconnections SBL2 mayextend in a second direction. The first sub-interconnections SBL1 mayinclude first protrusions P1 protruding in a first direction, and thesecond sub-interconnections SBL2 may include second protrusions P2protruding in a direction opposite to the first direction. Theprotrusions P1 and P2 may extend onto the third separation insulatinglayers 143.

Referring back to FIGS. 22A and 22B, the first sub-interconnections SBL1and the second sub-interconnections SBL2 are connected to differentadjacent bitlines through the second contacts 154. That is, the firstsub-interconnections SBL1 may be connected to the first bitline BL1, andthe second sub-interconnections SBL2 may be connected to the secondbitline BL2.

FIG. 26 is a perspective view of a vertical type memory device accordingto some embodiments of the inventive concept. FIG. 27A is a top planview of the vertical type memory device in FIG. 26, and FIG. 27B is across-sectional view taken along line A-A′ in FIG. 27A. Technicalfeatures similar to those of one embodiment explained with reference toFIG. 21 will not be explained, but differences therebetween will beexplained in detail.

Referring to FIGS. 26, 27A, and 27B, vertical pillars PL may includefirst to fourth vertical pillars PL1˜PL4 that are sequentially arrangedin a zigzag manner. The first and second vertical pillars PL1 and PL2may be coupled with each other at one side of string selection linesSSL1˜SSL3, and the third and fourth vertical pillars PL3 and PL4 may becoupled with each other at the other side thereof. The first and fourthvertical pillars PL1 and PL4 may be disposed at the edge of the stringselection lines SSL1˜SSL3, and the second and third vertical pillars PL2and PL3 may be disposed between the first vertical pillars PL1 and thefourth vertical pillars PL4. The second vertical pillars PL2 may beshifted from the first vertical pillars PL1 in a first direction. Thefourth vertical pillars PL4 may be shifted from the third verticalpillars PL3 in the first direction. Immediately adjacent verticalpillars may be spaced apart from each other in the first direction by,for example, two pitches of bitlines BL1˜BL4.

Sub-interconnections may include first to fourth sub-interconnectionsSBL1˜SBL4. The first sub-interconnections SBL1 may connect the thirdvertical pillars PL3 of the first string selection lines SSL1 to thesecond vertical pillars PL2 of the second string selection line SSL2.The second sub-interconnections SBL2 may connect the third verticalpillars PL3 of the second string selection lines SSL2 to the secondvertical pillars PL2 of the third string selection line SSL3. The thirdsub-interconnections SBL3 may connect the fourth vertical pillars PL4 ofthe first string selection lines SSL1 to the first vertical pillars PL1of the second string selection line SSL2. The fourthsub-interconnections SBL4 may connect the fourth vertical pillars PL4 ofthe second string selection lines SSL2 to the first vertical pillars PL1of the third string selection line SSL3. The first sub-interconnectionsSBL1 and the third sub-interconnections SBL3 may be alternately arrangedin the first direction, and the second sub-interconnections SBL2, andthe second sub-interconnections SBL2 and the fourth sub-interconnectionsSBL4 may be alternately arranged in the first direction. The first andfourth sub-interconnections SBL1 and SBL4 may be alternately arranged inthe second direction, and the second and third sub-interconnections SBL2and SBL3 may be alternately arranged in the second direction. The firstto fourth sub-interconnections SBL1˜SBL4 may be connected to adjacentother bitlines. For example, the first sub-interconnections SBL1 may beconnected to the first bitline BL1, the second sub-interconnections SBL2may be connected to the second bitline BL2, the thirdsub-interconnections SBL3 may be connected to the third bitline BL3, andthe fourth sub-interconnections SBL4 may be connected to the fourthbitline BL4.

First contacts 152 connect the vertical pillars PL1˜PL4 to thesub-interconnections SBL1˜SBL4. Second contacts 154 connect thesub-interconnections SBL1˜SBL4 to the bitlines BL1˜BL4. The firstcontacts 152 may be disposed on the vertical pillars PL1˜PL4, and thesecond contacts 154 may be disposed on or vertically aligned with thethird separation insulating layers 143. For example, the second contacts154 on the first and third sub-interconnections SBL1 and SBL3 may beshifted from the first contacts 152 in the first direction by half thepitch of bitlines, and the second contacts 154 on the second and fourthsub-interconnections SBL2 and SBL4 may be shifted from the firstcontacts in a direction opposite to the first direction by a quarterpitch of bitlines. The first to fourth sub-interconnections SBL1˜SBL4may extend in the second direction. The first and thirdsub-interconnections SBL1 and SBL3 may include first to thirdprotrusions P1 and P3 protruding in the first direction, respectively.The second and fourth sub-interconnections SBL2 and SBL4 may includesecond and fourth protrusions P2 and P4 protruding in a directionopposite to the first direction, respectively. For example, a protrusiondistance of the first and third protrusions P1 and P3 may be two timeslonger than that of the second and fourth protrusions P2 and P4. Thatis, the protrusion distance of the first and third protrusions P1 and P3may be larger to reach a corresponding bitline. The second contacts 154may be disposed on the protrusions P1˜P4. The protrusions P1˜P4 mayextend over first separation insulating layers 141 between gatestructures.

Referring to FIG. 27, an effective area to a single channel is reducedless than 3.3F² (2F×5F/3 channel) in the fifth embodiments of theinventive concept. Likewise, a unit cell area can be reduced to increaseintegration density. Furthermore, the number of bitlines selected by onestring selection gate, i.e., a page size may increase four times, due tothe arrangement of the vertical pillars PL. Thus, program and readspeeds can be improved.

FIG. 28 is a schematic block diagram illustrating an example of a memorysystem including a semiconductor device formed according to embodimentsof the inventive concept.

Referring to FIG. 28, an electronic system 1100 may include a controller1110, an input/output device (I/O) 1120, a memory device 1130, aninterface 1140, and a bus 1150. The controller 1110, the input/outputdevice 1120, the memory device 1130, and/or the interface 1140 may beconnected to each other through the bus 1150. The bus 1150 correspondsto a path along which data are transferred. The memory device 1130 mayinclude a semiconductor device according to embodiments of the inventiveconcept.

The controller 1110 may include at least one of a microprocessor, adigital signal processor, a microcontroller, and logic devices which arecapable of performing similar functions thereto. The input/output device1120 may include a keypad, a keyboard, a display device or the like. Thememory device 1130 may store data and/or commands. The interface 1140may function to transfer data to a communication network or receive datafrom the communication network. The interface 1140 may be a wiredinterface or a wireless interface. For example, the interface 1140 mayinclude an antenna or a wired/wireless transceiver. Although not shown,the electronic system 1100 may further include a high-speed DRAM deviceand/or an SRAM device as an operation memory device for improving theoperation of the controller 1110.

The electronic system 1110 may be applied to personal digital assistants(PDAs), portable computers, web tablets, wireless phones, mobile phones,digital music players, memory cards or all electronic devices capable oftransmitting and/or receiving data in wireless environments.

FIG. 29 is a schematic block diagram illustrating an example of a memorycard including a semiconductor device formed according to embodiments ofthe inventive concept.

Referring to FIG. 29, a memory card 1200 includes a memory device 1210.The memory device 1210 may include at least of the semiconductor devicesdisclosed in the foregoing embodiments. In addition, the memory device1210 may further include another type of semiconductor memory device(e.g., DRAM device and/or SRAM device, etc.). The memory card 1200 mayinclude a memory controller 1220 controlling data exchange between ahost and the memory device 1210. The memory device 1210 and/or thecontroller 1220 may include a semiconductor device according toembodiments of the inventive concept.

The memory controller 1220 may include a processing unit 1222controlling the overall operation of a memory card. The memorycontroller 1220 may include an SRAM 1221 used as a working memory of theprocessing unit 1222. In addition, the memory controller 1220 mayfurther include a host interface 1223 and a memory interface 1225. Thehost interface 1223 may include a data exchange protocol between thememory card 1200 and the host. The memory interface 1225 may connect thememory controller 1220 to the memory device 1210. Moreover, the memorycontroller 1220 may further include an error code correction (ECC) block1224. The ECC block 1224 may detect and correct errors of data read fromthe memory device 1210. Although not shown, the memory card 1200 mayfurther include a ROM device storing code data for interfacing with thehost. The memory card 1200 may be used as a portable data storage card.Alternatively, the memory card 1200 may be implemented with asolid-state disk (SSD) that may replace a hard disk of a computersystem.

FIG. 30 is a schematic block diagram illustrating an example of aninformation processing system on which a semiconductor device formedaccording to embodiments of the inventive concept is mounted.

Referring to FIG. 30, a flash memory system 1310 according toembodiments of the inventive concept is mounted on an informationprocessing system such as a mobile device or a desktop computer. Aninformation processing system 1300 according to embodiments of theinventive concept includes a flash memory system 1310 and a modem 1320,a central processing unit (CPU) 1330, a RAM 1340, and a user interface1350 that are electrically connected to a system bus 1360. The flashmemory system 1310 may have the substantially same configuration as theabove-mentioned memory system. Data processed by the CPU 1330 orexternally input data is stored in the flash memory system 1310. With anincrease in reliability, the flash memory system 1310 may reduceresources needed for error correction such that a high-speed dataexchange function may be provided to the information processing system1300. Although not shown in the drawing, it would be apparent to thoseskilled in the art that the information processing system 1300 mayfurther include an application chipset, a camera image processor (CIS),an input/output device, and the like.

In addition, a memory device or a memory system according to embodimentsof the inventive concept may be packaged as one of various types to besubsequently embedded. For example, a flash memory device or a memorysystem according to embodiments of the inventive concept may be packagedby one of PoP (Package on Package), Ball grid arrays (BGAs), Chip scalepackages (CSPs), Plastic Leaded Chip Carrier (PLCC), Plastic DualIn-Line Package (PDIP), Die in Waffle Pack, Die in Wafer Form, Chip OnBoard (COB), Ceramic Dual In-Line Package (CERDIP), Plastic Metric QuadFlat Pack (MQFP), Thin Quad Flatpack (TQFP), Small Outline (SOIC),Shrink Small Outline Package (SSOP), Thin Small Outline (TSOP), ThinQuad Flatpack (TQFP), System In Package (SIP), Multi Chip Package (MCP),Wafer-level Fabricated Package (WFP), and Wafer-Level Processed StackPackage (WSP).

As described so far, a unit cell area of a vertical memory device can bereduced to increase the density of the vertical memory device. Since thenumber of bitlines can increase as compared to conventionaltechnologies, a page size can increase and operating speed can beimproved.

Throughout the specification, features shown in one embodiment may beincorporated in other embodiments within the spirit and scope of theinventive concept.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Thus, theappearances of the phrases “in one embodiment” or “in an embodiment” invarious places throughout this specification are not necessarily allreferring to the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments.

Various operations may be described as multiple discrete steps performedin a manner that is most helpful in understanding the invention.However, the order in which the steps are described does not imply thatthe operations are order-dependent or that the order that steps areperformed must be the order in which the steps are presented.

While the inventive concept has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be apparent tothose of ordinary skill in the art that various changes in form anddetail may be made therein without departing from the spirit and scopeof the inventive concept as defined by the following claims.

The invention claimed is:
 1. A semiconductor device, comprising: asingle selection line extending in a first direction; first and secondvertically stacked memory cell strings arranged in a second directioncrossing the first direction, the first and second vertically stackedmemory cell strings commonly coupled to the single selection line; firstand second bit lines extending in the second direction, the first bitline spaced apart from the second bit line in the first direction; afirst sub-interconnection coupling the first vertically stacked memorycell string to the first bit line; and a second sub-interconnectioncoupling the second vertically stacked memory cell string to the secondbit line, wherein the vertically stacked memory cell strings arerespectively coupled to different bit lines.
 2. The device of claim 1,wherein the single selection line, the sub-interconnections, and the bitlines are sequentially provided on a substrate, wherein the verticallystacked memory cell strings are connected to the substrate, wherein thebit lines are provided on the vertically stacked memory cell strings,and wherein the sub-interconnections are provided between the verticallystacked memory cell strings and the bit lines.
 3. The device of claim 1,wherein each of the sub-interconnections has a longitudinal axis and ashort axis, a central part of each of the sub-interconnections protrudesin the first direction along the short axis, and the longitudinal axisextends in the second direction.
 4. A semiconductor device, comprising:first and second selection lines extending in a first direction, thefirst and second selection lines spaced apart from each other in asecond direction crossing the first direction; first and secondvertically stacked memory cell strings arranged in the second direction,the first vertically stacked memory cell string being coupled to thefirst selection line, the second vertically stacked memory cell stringbeing coupled to the second selection line; a bit line extending in thesecond direction; and a single-body sub-interconnection extending in thesecond direction coupling the first and second vertically stacked memorycell strings to the bit line wherein the single body sub-interconnectionhas one end part coupled to the first vertically stacked memory cellstring and another end part coupled to the second vertically stackedmemory cell string.
 5. The device of claim 4, wherein thesub-interconnection has a longitudinal axis and a short axis, wherein acentral part of the single body sub-interconnection protrudes in thefirst direction along the short axis, and wherein the longitudinal axisextends in the second direction.
 6. The device of claim 5, furthercomprising a separation insulating layer extending in the firstdirection, the separation insulating layer provided between the firstand second selection lines.
 7. The device of claim 6, wherein thecentral part of the single body sub-interconnection is verticallyoverlapped with the separation insulating layer.
 8. The device of claim6, wherein the single body sub-interconnection is connected to the firstbit line through the central part of the single bodysub-interconnection.
 9. The device of claim 5, further comprising: firstcontacts connecting the vertically stacked memory cell strings to thesingle body sub-interconnection; and a second contact connecting thesingle body sub-interconnection to the first bit line.
 10. The device ofclaim 9, wherein the second contact is shifted from the first contactsalong the first direction.
 11. A semiconductor device, comprising:first, second and third selection lines extending in a first direction,the selection lines spaced apart from each other in a second directioncrossing the first direction; first, second, third and fourth verticalpillars arranged in the second direction, the first vertical pillarbeing coupled to the first selection line, the second and third verticalpillars being commonly coupled to the second selection line, and thefourth vertical pillar being coupled to the third selection line; firstand second bit lines extending in the second direction, the first bitline spaced apart from the second bit line in the first direction; afirst sub-interconnection coupling the first and second vertical pillarsto the first bit line; and a second sub-interconnection coupling thethird and fourth vertical pillars to the second bit line.
 12. The deviceof claim 11, wherein each of the sub-interconnections has a longitudinalaxis and a short axis, the first sub-interconnection having a firstprotrusion protruding in the first direction along the short axis, thesecond sub-interconnection having a second protrusion protruding in anopposite direction to the first direction along the short axis, and thelongitudinal axis extending in the second direction.
 13. The device ofclaim 12, wherein the first sub-interconnection is connected to thefirst bit line through the first protrusion, and wherein the secondsub-interconnection is connected to the second bit line through thesecond protrusion.
 14. The device of claim 12, wherein the selectionlines, the sub-interconnections and the bit lines are sequentiallyprovided on a substrate, the device further comprising: a firstseparation insulating layer extending in the first direction, the firstseparation insulating layer provided between the first and secondselection lines.
 15. The device of claim 14, wherein the firstprotrusion is vertically overlapped with the first separation insulatinglayer.
 16. The device of claim 15, further comprising: cell gatesbetween the substrate and the selection lines, and wherein the verticalpillars penetrate the cell gates and are electrically connected to thesubstrate.
 17. The device of claim 16, further comprising: a secondseparation insulating layer extending in the first direction, the secondseparation insulating layer provided between the second and thirdselection lines, and wherein the first separation insulating layercontacts with the substrate, and the second separation layer providedabove the cell gates.
 18. The device of claim 17, wherein the firstprotrusion is vertically overlapped with the first separation insulatinglayer, and the second protrusion is vertically overlapped with thesecond separation insulating layer.
 19. The device of claim 16, furthercomprising: an information storage element between the cell gates andthe vertical pillars.
 20. The device of claim 16, wherein the firstsub-interconnection has a shorter length along the longitudinal axisthan that of the second sub-interconnection.